package problems.solved;

public class Problem11 {
	private static final int[][] GRID = {
		{ 8,  2, 22, 97, 38, 15,  0, 40,  0, 75,  4,  5,  7, 78, 52, 12, 50, 77, 91,  8},
		{49, 49, 99, 40, 17, 81, 18, 57, 60, 87, 17, 40, 98, 43, 69, 48,  4, 56, 62,  0},
		{81, 49, 31, 73, 55, 79, 14, 29, 93, 71, 40, 67, 53, 88, 30,  3, 49, 13, 36, 65},
		{52, 70, 95, 23,  4, 60, 11, 42, 69, 24, 68, 56,  1, 32, 56, 71, 37,  2, 36, 91},
		{22, 31, 16, 71, 51, 67, 63, 89, 41, 92, 36, 54, 22, 40, 40, 28, 66, 33, 13, 80},
		{24, 47, 32, 60, 99,  3, 45,  2, 44, 75, 33, 53, 78, 36, 84, 20, 35, 17, 12, 50},
		{32, 98, 81, 28, 64, 23, 67, 10, 26, 38, 40, 67, 59, 54, 70, 66, 18, 38, 64, 70},
		{67, 26, 20, 68,  2, 62, 12, 20, 95, 63, 94, 39, 63,  8, 40, 91, 66, 49, 94, 21},
		{24, 55, 58,  5, 66, 73, 99, 26, 97, 17, 78, 78, 96, 83, 14, 88, 34, 89, 63, 72},
		{21, 36, 23,  9, 75,  0, 76, 44, 20, 45, 35, 14,  0, 61, 33, 97, 34, 31, 33, 95},
		{78, 17, 53, 28, 22, 75, 31, 67, 15, 94,  3, 80,  4, 62, 16, 14,  9, 53, 56, 92},
		{16, 39,  5, 42, 96, 35, 31, 47, 55, 58, 88, 24,  0, 17, 54, 24, 36, 29, 85, 57},
		{86, 56,  0, 48, 35, 71, 89,  7,  5, 44, 44, 37, 44, 60, 21, 58, 51, 54, 17, 58},
		{19, 80, 81, 68,  5, 94, 47, 69, 28, 73, 92, 13, 86, 52, 17, 77,  4, 89, 55, 40},
		{ 4, 52,  8, 83, 97, 35, 99, 16,  7, 97, 57, 32, 16, 26, 26, 79, 33, 27, 98, 66},
		{88, 36, 68, 87, 57, 62, 20, 72,  3, 46, 33, 67, 46, 55, 12, 32, 63, 93, 53, 69},
		{ 4, 42, 16, 73, 38, 25, 39, 11, 24, 94, 72, 18,  8, 46, 29, 32, 40, 62, 76, 36},
		{20, 69, 36, 41, 72, 30, 23, 88, 34, 62, 99, 69, 82, 67, 59, 85, 74,  4, 36, 16},
		{20, 73, 35, 29, 78, 31, 90,  1, 74, 31, 49, 71, 48, 86, 81, 16, 23, 57,  5, 54},
		{ 1, 70, 54, 71, 83, 51, 54, 69, 16, 92, 33, 48, 61, 43, 52,  1, 89, 19, 67, 48}
	};
	public static void main(String[] args) {
		int horizontalMax = walkHorizontal();
		int verticalMax = walkVertical();
		int diagonalMax1 = walkDiagonal1();
		int diagonalMax2 = walkDiagonal2();
		
		System.out.printf("horizontalMax=%d, verticalMax=%d, d1=%d, d2=%d%n", horizontalMax, verticalMax, diagonalMax1, diagonalMax2);
	}

	private static int walkVertical() {
		int max = 0;
		for (int x = 0; x < GRID.length - 3; x++) {
			for (int y = 0; y < GRID[0].length; y++) {
				int product = productV(x, y);
				if (product > max) {
					max = product;
				}
			}
		}
		return max;
	}
	
	private static int productV(int x, int y) {
		int product = 1;
		for (int i = 0; i < 4; i++) {
			product *= GRID[x+i][y];
		}
		return product;
	}

	private static int walkHorizontal() {
		int max = 0;
		for (int x = 0; x < GRID.length; x++) {
			for (int y = 0; y < GRID[0].length - 3; y++) {
				int product = productH(x, y);
				if (product > max) {
					max = product;
				}
			}
		}
		return max;
	}

	private static int productH(int x, int y) {
		int product = 1;
		for (int i = 0; i < 4; i++) {
			product *= GRID[x][y+i];
		}
		return product;
	}
	
	private static int walkDiagonal1() {
		int max = 0;
		for (int x = 0; x < GRID.length - 3; x++) {
			for (int y = 0; y < GRID[0].length - 3; y++) {
				int product = diagonalProduct1(x, y);
				if (product > max) {
					max = product;
				}
			}
		}
		return max;
		
	}
	
	private static int diagonalProduct1(int x, int y) {
		int product = 1;
		for (int i = 0; i < 4; i++) {
			product *= GRID[x+i][y+i];
		}
		return product;
	}

	private static int walkDiagonal2() {
		int max = 0;
		for (int x = 0; x < GRID.length - 3; x++) {
			for (int y = 0; y < GRID[0].length - 3; y++) {
				int product = diagonalProduct2(x, y);
				if (product > max) {
					max = product;
				}
			}
		}
		return max;
	}
	
	private static int diagonalProduct2(int x, int y) {
		int product = 1;
		for (int i = 0; i < 4; i++) {
			product *= GRID[x+(3-i)][y+i];
		}
		return product;
	}
}
